[PHP] php聚合式迭代器的基础知识点及实例代码

class MainIterator implements Iterator
{
  private $var = array();
  public function __construct($array)  //构造函数, 初始化对象数组
  {
    if (is_array($array)) {
    $this->var = $array;
    }
  }
 
  public function rewind() {   
    echo "rewinding\n";
    reset($this->var);  //将数组的内部指针指向第一个单元
  }
 
  public function current() {
    $var = current($this->var);  // 返回数组中的当前值
    echo "current: $var\n";
    return $var;
  }
 
  public function key() {
    $var = key($this->var);     //返回数组中内部指针指向的当前单元的键名
    echo "key: $var\n";
    return $var;
  }
 
  public function next() {
    $var = next($this->var);   //返回数组内部指针指向的下一个单元的值
    echo "next: $var\n";
    return $var;
  }
 
  public function valid() {
  return !is_null(key($this->var); //判断当前单元的键是否为空
  }
}

<?php
class myData implements IteratorAggregate {
  public $property1 = "Public property one";
  public $property2 = "Public property two";
  public $property3 = "Public property three";
  public function __construct() {
    $this->property4 = "last property";
  }
  public function getIterator() {
    return new ArrayIterator($this);
  }
}
$obj = new myData;
foreach($obj as $key => $value) {
  var_dump($key, $value);
  echo "\n";
}
?>

string(9) "property1"
string(19) "Public property one"
string(9) "property2"
string(19) "Public property two"
string(9) "property3"
string(21) "Public property three"
string(9) "property4"
string(13) "last property"